1. Field of the Invention
The present invention is in the field of electromechanical devices designed to provide anti-theft protection to cargo trailers and like equipment equipped with air brakes. More particularly, the present invention is directed to a device or system that prevents unauthorized release of the locked brake actuator rod of trailers, tractors and of like equipment that are equipped with a dual chamber air brake system.
2. Brief Description of the Prior Art
Cargo-trailers, tractors and like equipment are vulnerable to theft particularly when parked or stored in remote or unpopulated locations where audible alarms are ineffective. In case of trailers and like equipment that do not have their own motive power (engine), compressed air for operating the brake system is supplied through a conduit from the tractor or truck that pulls the trailer. Such trailers and like towed equipment, as well as many tractors and trucks, are equipped with a dual chamber brake system that operates in such manner that the brakes are locked when pressurized air is not available. In order to take such a trailer without authorization, that is to steal it, the thief typically hooks the trailer to the thief""s tractor which then supplies pressurized air to the dual chamber brake system of the trailer. In other words, by hooking up the thief""s tractor""s or truck""s air pressure conduit to the brake system of the trailer, the thief is able to pull the trailer with the brakes operating normally. To this date and to the best knowledge of the present inventor, the state-of-the-art has attempted to prevent or discourage the theft of cargo-trailers by providing devices that make it difficult for an unauthorized person to access the trailer""s hitch or xe2x80x9cfifth wheelxe2x80x9d, or by providing a keyed cover (xe2x80x9cglad handxe2x80x9d cover) that prevents attachment of a pressurized air conduit to the pressurized air inlet of the dual chamber air brake system of the trailer. Experience has shown however, that a determined thief circumvents these devices relatively easily. Therefore, there is still a serious need in the art for a device or system that renders the dual chamber air brake system of a trailer (or of a tractor) inoperational for unauthorized users. The present invention provides such a system.
It is an object of the present invention to provide a secure and difficult to circumvent locking device for the brakes of a trailer, tractor or other vehicle equipped with dual chamber air brake system, which locking device can be released only by an authorized user.
It is another object of the present invention to provide the locking device that meets the above-noted objective, and which operates within the interior of the dual chamber air brake system, thereby making it more difficult and time consuming to disassemble or inactivate the locking device and make unauthorized use of the trailer, tractor or other vehicle equipped with the device.
The foregoing and other objects and advantages are attained by a device that has means mounted within the interior of the dual chamber brake system to prevent a brake actuator rod from being retracted into its non-braking operative position even when pressurized air is supplied to the dual chamber brake system. The means for preventing such retraction, that is the means for locking the actuator rod into its position where the brakes are fully engaged, are activated and deactivated to respectively lock or to permit normal operation of the dual chamber brake system by an electro mechanical device, such as a servo-motor, solenoid or the like which is actuated from the outside by the use of a coded signal that is likely to be transmitted only by an authorized user. Alternatively a valve is incorporated within the interior of the air inlet of the dual chamber brake system which in its locked position prevents pressurized air from being supplied to one of the dual chambers, thereby preventing the release or retraction of the brake actuator rod into its non-braking operative position, The valve is operated by an electro mechanical device, such as a servo-motor or solenoid and is responsive to a coded signal that is likely to be transmitted only by an authorized user.